Field of the Invention
The present invention relates to a control apparatus, image processing apparatus, control method, and non-transitory computer-readable storage medium.
Description of the Related Art
When forming and outputting an image, local (neighbourhood) image processing such as spatial filter processing is sometimes applied. This local image processing is image processing of performing any calculation by using pixels in a spatial filter region, including a pixel to be processed (to be referred to as a processing pixel hereinafter). The local (neighbourhood) image processing enables, for example, edge emphasis, blur processing, and resolution conversion of converting an input image into an image of a desired size by enlargement or reduction. In the following description, this local (neighbourhood) image processing will be called “filter processing”.
An image processing apparatus includes a filter circuit for a function of performing the above-described filter processing on an input image. In general, most of reading devices such as a scanner, printing devices such as a printer, and display devices such as a display can support a color image/color original (for example, an image having a plurality of colors such as an RGB color image or a CMYK color image). Image processing apparatuses mounted in many of these devices are often constructed basically for color processing. For example, the image processing apparatus includes filter circuits that process three colors for an RGB color image or four colors for a CMYK color image. In many cases, a general filter circuit is designed to be able to arbitrarily change the setting of a filter coefficient used in filter processing by a register setting or the like, so that this circuit can be used not only for one process but also for another processing. Hence, filter circuits corresponding to respective colors can be identical. The image processing apparatus can be parallelly equipped with filter circuits by the number of supported colors, such as three filter circuits for an RGB color image or four filter circuits for a CMYK color image. The device can include a plurality of image processing apparatuses corresponding to respective colors. For example, even when the image processing apparatus is equipped with only a filter circuit for one color, the whole device can support color processing by arranging image processing apparatuses by the number of supported colors. The unit of parallelized processing (granularity) corresponding to the number of colors in the color processing-based processing apparatus varies from a small unit of the circuit level to a large unit of the system level such as the processing apparatus.
When a monochrome (single-color) image is input to the color processing-based processing apparatus, the unit of parallelized processing (granularity) as described above can be used efficiently. By efficiently using the unit of processing, the image processing apparatus can increase the processing speed of a single-color image, compared to the processing speed of a color image.
For example, according to a technique described in Japanese Patent Laid-Open No. 2000-148996, an image processing apparatus includes a plurality of image processors. The image processing apparatus first determines which of a single-color original and a color original is an input original. For the single-color original, the image processing apparatus performs distributed parallel processing by dividing input image data and assigning the divided data to the plurality of image processors. Japanese Patent Laid-Open No. 2000-148996 also describes that when monochrome (single-color) images span a plurality of pages, the plurality of image processors execute the processes of the respective pages to increase the speed by distributed parallel processing.
Japanese Patent Laid-Open No. 2009-141430 describes an image processing apparatus including a plurality of reduction circuits. When an input original is a monochrome original having a plurality of pages, the originals of these pages are respectively assigned to the reduction circuits to increase the speed of original reduction processing by distributed parallel processing. Japanese Patent Laid-Open No. 2009-141430 also describes that some pages are divided and respectively assigned to the reduction circuits to perform distributed parallel processing.
One of color image/color original data storage formats is a dot sequential format, and the dot sequential format is widely employed in built-in devices such as a scanner, a printer, and a display. In the dot sequential format, a plurality of color components constituting one pixel are packed in one data unit and handled. The data storage method of the dot sequential format therefore has an advantage of reading out at once a plurality of color components constituting one pixel by one data access. When the data storage method of the dot sequential format is adopted, the image processing apparatus executes image processing on, as one unit of processing (granularity), one pixel having a plurality of color components that can be read out at once. An image processing apparatus supporting the dot sequential format need not particularly perform difficult control, and can be implemented by employing general image processing circuits that perform a pipeline operation synchronously in one pixel unit.
However, Japanese Patent Laid-Open Nos. 2000-148996 and 2009-141430 do not describe a method of increasing the speed by distributed parallelization of the performance of image processing at the time of monochrome (single-color) processing in a color processing-based image processing apparatus supporting image data of the dot sequential format.
The present invention has been made in consideration of the above situation, and provides a technique of increasing the speed by distributed parallelization of the performance of image processing at the time of single-color processing in an image processing apparatus capable of executing color processing supporting image data of the dot sequential format.